Organo-titanium compounds and zinc dicarboxylates as synergistic esterification catalyst



United States Patent 3,418,359 ORGAN O-TITANIUlVI COMPOUNDS AND ZINCDICARBOXYLATES AS SYNERGISTIC ESTERI- FICATION CATALYST Walter P. Barie,In, Pittsburgh, Norman W. Franke, Penn Hills Township, Allegheny County,and Arthur C. Whitaker, Pittsburgh, Pa., assignors to Gulf Research &Development Company, Pittsburgh, Pa., a corporation of Delaware NoDrawing. Filed Apr. 18, 1963, Ser. No. 273,846 12 Claims. (Cl. 260-475)This invention relates to an improved catalyst for use in esterificationprocesses.

A large number of organo-metallic and metallo-organo compounds are knownin the art as catalysts for the direct esterification of alcohols withorganic acids. These catalysts have certain advantages, especially forthe reaction of higher molecular weight alcohols (C plus) and organicacids in producing light-colored esters which are particularly valuableas plasticizers in the production of light-colored plastics. Theseorgano-metallic and metalloorganic compounds sufier, however, from thedisadvantage of a slow reaction rate. It has now been found that theadvantages of the use of these catalysts can be retained and anunexpected increase in reaction rate achieved by employing selectedmixtures of these compounds.

In accordance with the invention, an improved esterification process isachieved by contacting an alcohol with an organic acid in the presenceof a catalyst comprising at least one qnadrivalent titanium-organiccompound wherein the titanium is directly connected to four oxygen atomsand at least one zinc dicarboxylate.

The preferred quadrivalent titanium-organic compounds, wherein thetitanium is directly connected to four oxygen atoms, can be representedby the general formula:

Z O-Ii Y where n is an integer between 1 and 60;

X is a radical selected from the group consisting of OR and where R isas defined below;

X is a radical selected from the group consisting of OR and where R isas defined below;

Z is a radical selected from the group consisting of R; Ti(OR)s; and

when Y is Patented Dec. 24, 1968 where X and X are as defined above andR is as defined below;

Y is a radical selected from the group consisting of OR;

where X and X are as defined above and R is as defined below; and whereR is a radical selected from the group consisting of an aliphaticradical having from 2 to 18 carbon atoms; an alicyclic radical havingbetween 1 and 3 rings, between 5 and 6 carbon atoms per ring, andbetween 5 and 18 carbon atoms per molecule; and an aromatic radicalhaving between 1 and 3 rings and between 6 and 18 carbon atoms permolecule.

Where n in the general formula above is one, the titanium compounds aremonomers. Examples of suitable monomeric titanium compounds include:

(1) the tetrahydrocarbyl titanates represented by the general formula:

Ti(OR) where R is as defined above. By hyd rocarbyl is meant amonovalent radical derived from a compound consisting of carbon andhydrogen. Examples of suitable tetrahydrocarbyl titanates includetetraethyl titanate; tetrapropyl titanate; tetraisopropyl titanate;tetrabutyl titanate; tetraisooctyl titanate; tetrastearyl titanate;tetrabenzyl titanate; tetracyclohexyl titanate; tetraphenyl titanate;tetradodecyl titanate and tetraallyl titanate, and

(2) the dititanates represented by the general formula:

(RO) Ti-O-Ti(OR) 3 where R is as defined above. Suitable specificexamples of these compounds include hexaethyl dititanate; hexapropyldititanate; hexaisopropyl dititanate; hexaisooctyl dititanate;hexastearyl dititanate; hexabenzyl dititanate; hexaphenyl dititanate;hexacyclohexyl dititanate; triethyltripropyl dititanate;trioctyltriphenyl dititanate and hexadodecyl dititanate.

Where n in the general formula above is more than one, a polymerresults. The polymer can be cyclic, in which case both Z and Y are XIIOTi-X where X and X are as defined above. The polymer can be a straightchain polymer with terminating groups Y and Z selected from the class asdefined above.

The zinc dicarboxylates which are useful as co-catalysts in the processof this invention may be represented by the general formula:

where R' can be an aliphatic radical having from 1 to 18 carbon atoms;an alieyclic radical having between 1 and 3 rings, between 5 and 6carbon atoms per ring, and between 5 and 18 carbon atoms per molecule;and an aromatic radical having between 1 and 3 rings and between 6 and18 carbon atoms per molecule. Suitable specific examples of zinccompounds which can be employed include zinc acetate; zinc propionate;zinc butyrate; zinc octanoate; zinc laurate; zinc stearate; Zinccyclohexane carboxylate; zinc cyclopentane carboxylate; zinc benzoate;zinc maleate; Zinc salicylate; zinc caproate; zinc naphthenate; zincphenanthroate and zinc oleate.

The subject process is applicable to the reaction of an organic acidwith an alcohol to form a product comprising an ester group. By anorganic acid is meant any compound containing between 1 and 8 carboxylgroups, COH, or the inner anhydride derivatives thereof. The preferredorganic acids are those wherein the only functional groups are between 1and 8 carboxyl groups or the inner anhydride derivatives thereof. Thepreferred organic acids have between 1 and 4 carboxyl groups permolecule. The organic acid can have between 2 and 30 carbon atoms permolecule with preferred organic acids having between 2 and 20 permolecule.

Suitable organic acids include any aliphatic, alicyclic or aromaticmonoor polycarboxylic acids or inner anhydride derivatives thereof. Byan inner anhydride derivative thereof is meant a cyclic anhydride formedby the elimination of water and cyclization of two carboxyl groups onthe same molecule. The alicyclic acids can have between and 6 ringcarbon atoms and between 1 and 3 rings. The aromatic acids can havebetween 1 and 3 rings. The monohydroxy, monohalo, monoamino and monoketoorganic acids can also be employed. The most preferred organic acids arethe aromatic carboxylic acids or the inner anhydride derivatives thereofhaving between 1 and 2 rings, between 2 and 4 carboxyl groups, andwherein the only functional groups are the carboxyl groups. Examples ofsuitable organic acids include acetic; propionic; butyric; isobutyric;valeric; hexaonic; heptanoic; octanoic; pelargonic; lauric; myristic;palmitic; stearic; decanoic; tridecanoic; acrylic; methacrylic;crotonic; maleic; fumaric; vinylacetic; undecylenic; linolenic;cyclopropanecarboxylic; cyclobutanecarboxylic; cyclopentanecarboxylic;cyclohexylcarboxylic; cycloheptanecarboxylic; benzoic; phenylacetic;henylpropionic; triphenylacetic; 0-, mand p-phthalic; para-nitrobenzoic;para-chlorobenzoic; para-dodecylbenzoic; alpha naphthoic; betanaphthoic; pyruvic; levulinic; benzoylacetic; alpha-benzoylbutyric;alpha-aminoisobutyric; beta-aminopropionic; o-, mor phydroxybenzoic;ethoxyacetic; alpha-ethoxyisobutyric; furfuroic; alpha-fluoropropionic;beta-bromopropionic; alpha-chloroacetic; trifluoroacetic; malonic;succinic; glutaric; adipic; pimelic; azelaic; sebacic; pentadecane-l,l5-dicarboxylic; pentacosane-l,25-dicarboxylic; cyclohexane-1,2-dicarboxylic; benzophenonedicarboxylic; 1,2,3-propanetricarboxylicacid; trimellitic; l,3,5-cyclohexanetricarboxylic; pyromellitic;3,4,3',4'-benzophenonetetracarboxylic; 2,3,5,6,2',3',5,6'benzophenoneoctacarboxylic; lactic; beta-hydroxypropionic;alpha-hydroxybutyric; betahydroxybutyric; succinic anhydride; glutaricanhydride; maleic anhydride; citraconic anhydride; itaconic anhydride;phthalic anhydride; pyromellitic dianhydride; 3,4, 3,4'benzophenonetetracarboxylic dianhydride; and 2,3,5,6,2',3',5',6'benzophenoneoctacarboxylic tetraanhydride.

By an alcohol is meant any organic compound containing between 1 and 4alcoholic hydroxyl groups, wherein at least one of said alcoholichydroxyl groups is attached to a carbon atom having at least onesubstituent hydrogen atom. The alcohol can have between 1 and 37 carbonatoms per molecule, preferably between 4 and 20 and most preferablybetween 8 and 13 carbon atoms per molecule. The monohydric alcohols canbe represented by the general formula:

where R and R can be the same or different and are selected from thegroup consisting of hydrogen and R' as defined for the zinc compoundsabove. Specific examples of suitable monohydric alcohols includen-butyl; isobutyl; sec-butyl; n-amyl; isoamyl; 2-methylpentanol-3;noctyl; 7-methylheptanol-1; capryl; S-methylnonanol-l; lauryl; llmethyldodecanol 1; tetradecyl; hexadecyl; stearyl; benzyl; phenylethyl;o-, mand p-methylbenzyl; hexanol-3; decanol-4; dodecanol-S; allyl;2-octenol-l; 3- nonenol-l; 4-decenol-l; 5-dodecenol-1; 6-dodecenol-2; 5-octacosenol-l6; 4-tricontenol-l2; heptacontanol-l4; and cyclohexanol.

Mixtures of these alcohols can also be employed. Particularly suitablemixtures are the reaction products obtained by the hydroformylation andsubsequent hydrogenation of at least one olefin having between 3 and 19carbon atoms per molecule, and more particularly those mixtures ofalcohols obtained as the reaction product of the hydroformylation andsubsequent hydrogenation of at least one olefin having between 7 and 12carbon atoms per molecule. For example, hexyl, isooctyl, decyl andtridecyl oxo alcohols are available commercially.

Polyhydric alcohols containing between 2 and 4 alcoholic hydroxyl groups(e.g., glycols) can also be employed. In general, the polyhydricalcohols which are used as reactants in the process of this inventionhave between 4 and 30 carbon atoms per molecule and preferably havebetween 7 and 15 carbon atoms per molecule. Suitable examples ofpolyhydric alcohols include butylene glycol; pentadecane-l,l5-diol;pentamethylene glycol; neopentyl glycol; 1,2,3-trihydroxybutane;trimethylolheptane; and pentaerythritol.

From the definition of the organic acid and alcohol above, it can beseen that the subject process relates to the reaction of an organiccompound having at least one carboxyl group with an organic compoundhaving at least one alcoholic hydroxyl group to form a productcomprising an ester group. If at least one of the two reactants ismonofunctional then a monomeric ester will be obtained as the product.By a monomeric ester is meant an organic compound containing at leastone ester group per molecule but no more ester groups per molecule thanthe corresponding number of carboxyl groups in the organic acid reactantor the number of alcoholic hydroxyl groups in the alcoholic reactantfrom which the monomeric ester is prepared. For example, the reaction ofnormal octyl alcohol and butanoic acid produces the monomeric esteroctyl butanoate, while the reaction of normal octyl alcohol withphthalic anhydride produces the monomeric diester dioctyl phthalate.

By a polyester is meant the reaction product of an organic acid having 2or more carboxyl groups per molecule with an alcohol having 2 or morealcoholic hydroxyl groups per molecule. The polyester usually has amolecular weight between about 500 and 10,000, or more. The improvedcatalysts of this invention are suited to the preparation of eithermonomeric esters or polyesters.

Theoretically, to produce an ester, one mol of a monohydric alcohol isneeded for each mol of a monocarboxylic acid. When a polyfunctionalreactant is employed, a molar increase in the monofunctional reactantcorresponding to the number of functional groups in the polyfunctionalreactant must be employed to obtain a theoretically complete reaction.The degree of completion and completion rate are improved, however, bythe presence of a molar excess of one or the other of the reactants overthe theoretical amount needed for complete conversion. It is preferredfor ease of recovery to have an excess within the reaction zone of thatreactant which distills at the lower temperature. Since at least one ofthe reactants may be polyfunctional, it is preferred to discuss themolar ratio of reactants in terms of the molar ratio of alcoholichydroxyl groups in the alcohol reactant to carboxyl groups in theorganic acid reactant. As noted :above, the term organic aci is meant toinclude the inner anhydride derivatives thereof. The number of carboxylgroups per molecule of inner anhydride is taken to mean the number ofcarboxyl groups which would be present in the hydrated form of theanhydride. Thus, phthalic and maleic anhydrides would be considered tohave two carboxyl groups per molecule. Thus, the molar ratio ofalcoholic hydroxyl groups in the alcohol reactant to carboxyl groups inthe organic acid reactant can be between 1:30 and 30:1 with preferredmolar ratios between 1:5 and 5:1.

To illustrate the above, if one mol of octyl alcohol is employed as thealcohol reactant and a 1:1 molar ratio of hydroxyl groups in the alcoholreactant to carboxyl groups in the organic acid reactant is desired,then the molar amounts of acetic acid (a monocarboxylic acid); adipicacid (a dicarboxylic acid); phthalic anhydride and pyromelliticdianhydride as the organic acid reactants should be 1; 0.5; 0.5; and0.25 respectively.

The amount of titanium catalyst calculated as titanium to be employedcan vary between 0.001 and 5 weight percent titanium based on the weightof the expected ester with preferred amounts of the titanium catalystbeing 0.01 and 1 percent by weight titanium of the expected ester.

The weight ratio of the zinc catalyst to the titanium catalyst, based onthe weight of the metals alone, can be between 1:5 and 5:1 andpreferably the weight ratio of the zinc to the titanium catalyst, basedon the weight of the metals alone, can be between 122 and 2:1.

The function of reaction temperature is to increase the rate ofreaction. In general, the temperature of reaction can be between 70 C.and 300 C. depending upon the boiling point of the chosen reactants. Thebest temperature to be employed for any particular acid or alcohol mayreadily be determined by one skilled in the art. In general, the highermolecular weight alcohols and acids react more slowly and the higherreaction temperatures are desired to increase the reaction rate. Thetemperature of the reaction must be high enough to remove the water ofthe esterification, but not so high that the acid or alcohol chargestock is removed. It is sometimes preferable to employ an =azeotropingagent, such as benzene, to remove the water and thus allow for the useof lower reaction temperatures. Preferred reaction temperatures arebetween 100 C. and 250 C. with the most preferred reaction temperaturesbeing between 135 C. and 200 C.

Any reaction pressure can be employed. Atmospheric pressure ispreferred. The use of lower reaction pressures allows the use of lowerreaction temperatures since the water of esterification will be removedmore easily. The use of pressures in excess of atmospheric allows theuse of higher temperatures. Thus, pressures between 5 and 250 p.s.i.a.,or higher can be employed with the preferred pressure being atmosphericpressure. Reaction conditions that are best suited for the type andconcentration of alcohol, organic acid and catalyst and for theparticular apparatus may readily be determined by one skilled in the artfamiliar with such processes, in accordance with the teachings above.

It is usually desirable to maintain in inert atmosphere, such asnitrogen, carbon dioxide or helium gas, over the reaction mixture toreduce oxidation of the charge stock and products.

The reaction time is usually between 0.5 and 30 hours or more dependingon the particular reactants and the degree of completion desired. Ingeneral, the lower molecular weight and monofunctional reactants reactmore quickly. Reaction times less than 30 minutes usually result inconversions which are too low while the reaction times above about 30hours are usually impractical.

It is preferred that the reactants be liquid under reaction conditionsand, in addition, it is preferred that the reactants be miscible. Inmany instances, however, the acid reactant is a solid polycarboxylicacid, for example citric acid, whose solubility in organic alcohols, par

ticularly the higher alcohols, may be limited. In certain instances,therefore, it may be desirable to employ a common inert solvent ordiluent to dissolve those reactants before entering the reaction zone.These solvents sometimes serve a dual function of an azeotroping agentto remove the water of the esterification. Any diluents which wouldreact with the charge components should, of course, be avoided. Suitablediluents include saturated aliphatic and alicyclic hydrocarbons havingbetween 5 and 30 carbon atoms per molecule and preferably between 5 and16 carbon atoms per molecule, and aromatic hydrocarbons having between 1and 3 rings and between 6 and 18 carbon atoms per molecule. Suitablespecific examples of inert diluents include pentane; hexane; heptane;decane; cetane; cyclohexane; cyclopentane; benzene; toluene; o-xylene;m-xylene and p-xylene.

The invention will be further described with relation to the followingspecific examples.

In all of the examples the following procedure was employed except whereotherwise indicated. The organic acid reactant'for all of the exampleswas phthalic anhydride. The alcohol reactant was either a mixture ofisooctyl or tridecyl oxo alcohols obtained by the hydroformylation andsubsequent hydrogenation of a mixture of branched-chain heptenes andbranched-chain C olefins, respectively. The mixture of branched-chainheptenes was the 87 F. to 94 P. fraction of the product from thealkylation of propylene and butene. The C olefins are the 186 F. to 195F. fraction of the product from the sulfuric acid polymerization ofpropylene.

In each run, one mol (148 grams) of phthalic anhydride was reacted withapproximately 2.1 mols of the oxo alcohol (5% excess) at a temperatureof 180 C. using a nitrogen purge gas (0.13 liter per minute). Fiftymilliliters of heptane were added, along with the desired catalyst orcatalyst mixture. The heptane was added as an azeotroping agent as anaid in removing the water overhead. The rate of esterification wasfollowed by measuring the water of the esterification at various timeintervals.

In each example the product was treated with a 1 percent sodiumhydroxide solution until basic to pH paper. The aqueous alkaline layerwas removed and the organic layer was washed with hot water (70 to C.)until the washing was neutral to pH paper. The product was distilled atreduced pressure to less than one mm. of Hg) to remove the water and theheptane. Any unreacted alcohol was also removed at reduced pressure(less than 1 mm. of Hg). The distillation temperature was then taken to150 C. for isooctyl alcohol and 200 C. for tridecyl alcohol at thereduced pressure. The product was then treated with 2 grams of activatedcarbon (about 0.5 percent by weight) at 90 C. for one-half hour andfiltered using Celite and a fritted glass filter.

Example 1 In the run for this example, 2.1 mols (273 grams) of 0x0isooctyl alcohol, whose properties are given in Table I below, wasreacted with phthalic anhydride as described above using 4.58 grams (0.1percent by weight of titanium based on the weight of the expected esterdiisooctylphthalate) of tetra(2-ethylhexyl) titanate as the catalyst.The weight percent conversion of phthalic anhydride after a six hourreaction period was 95.0 and the APHA color (by ASTM test methodD120954) of the ester product was 15.0. The weight percent conversionwas calculated by dividing the weight of water produced in the reactionby the theoretical weight of water which should have been produced.

TABLE I.TYPIGAL INSPECTIONS OF ALCOHOLS Isooctyl Tridecyl alcoholalcohol Specific gravity, 20l20 G. (68/68 F.) 0.833 0.845 Color, APHA(by ASIM D-1209-54) 3 3 Refractive Index, m) 20 1. 4312 l. 4473 Sulfur,p.p.m 3 1 Water, percent by Weight 0. 020 0.008 Acidity as acetic acid,percent by w g 0.001 0.003 Ca carbonyl content, percent by weight 0.01Ola carbonyl content, percent by Weight 0. 04 Distillation: ASTM D1078:

Initial boiling point, O 185 254. 9

Dry Point, C 188. 5 262. 9

Example 2 Example 1 was repeated except the tetra(2-ethylhexyl) titanatecatalyst was replaced by 1.31 grams (0.1 percent by weight of zinc basedon the weight of the expected ester) of zinc acetate. The weightper-cent conversion of phthalic anhydride after a six hour reactionperiod was 87.3 and the APHA color of the ester product was 10.0.

Example 3 Example 1 was repeated except the catalyst consisted of 2.29grams (0.05 percent by weight of titanium based on the weight of theexpected ester) of tetra(2-ethylhexyl) titanate and 0.66 gram (0.05percent by weight of zinc based on the weight of the expected ester) ofzinc acetate. The weight percent conversion of phthalic anhydride aftera five hour reaction period was 99.5 percent and the APHA color of theester product was 10.0.

A comparison of Examples 1, 2 and 3 shows that the use of a mixture oftetra(2-ethylhexyl) titanate and zinc acetate gives more than theadditive and expected results over the use of either catalyst alone inthe same total catalyst concentration in the reaction mixture. That is,a greater weight percent conversion (99.5) was achieved using themixture of titanium and zinc than with either the titanium (95.0) or thezinc (87.3) catalyst alone in a shorter reaction time, i.e. five hoursfor the catalyst mixture compared to six hours for the individualcatalyst components. In addition, the color of the ester was as good aswhen using the zinc acetate alone and better than when using thetitanium catalyst alone.

Example 4 Example 3 was repeated except the alcohol reactant was 420grams (2.1 mols) of 0x0 tridecyl 'alco hol, whose properties are givenin Table I above. The weight precent cnversion of phthalic anhydrideafter a six hour reaction period was 98.5 and the APHA color of theester product was 15.0.

A comparison of Example 4 with Examples 1 and 2 shows again theunexpected additive effect of employing a mixture of the titanium andzinc compounds of this invention. The weight percent conversion ofphthalic anhydride Was higher (98.5 weight percent) than when either thetitanium (95 weight percent) or zinc (87.3 weight percent) compoundswere used alone, despite the fact that a higher molecular weight alcoholwas used as areactant.

Resort may be had to such variations and modifications as fall withinthe spirit of the invention and the scope of the appended claims.

We claim:

1. A process for the production of a light colored monomeric ester whichcomprises contacting an aromatic organic acid reactant having between 1and 4 carboxyl groups per molecule with a saturated unsubstitutedaliphatic alcohol reactant having between 4 and 37 carbon atoms permolecule, and wherein at least one of the two reactants ismonofunctional under esterification conditions in the presence of acatalyst comprising at "least one quadrivalent titanium-organic compoundhaving the formula:

Ti(OR) where R is selected from the group consisting of an acyclicsaturated or olefinically unsaturated hydrocarbon radical having between1 and 18 carbon atoms; cyclohexyl and phenyl; and at least one zincdicarboxylate repre sented by the general formula:

where R is selected from the group consisting of an acyclic saturated orolefinically unsaturated hydrocarbon radical having between 1 and 18carbon atoms; a single ring alicyclic hydrocarbon radical having between5 and 6 carbon atoms per ring and between 5 and 18 carbon atoms permolecule; and a single ring aromatic hydrocarbon or hydroxy substitutedaromatic hydrocarbon radical having between 6 and 18 carbon atoms permolecule.

2. A process according to claim 1 wherein the aromatic organic acid isphthalic anhydride.

3. A process according to claim 1 wherein the zinc dicarboxylate is zincacetate.

4. A process according to claim 1 wherein the titanium organic compoundis tetra(2-ethylhexyl)titanate.

5. A process according to claim 1 wherein the alcohol reactant comprisesthe reaction product obtained by the hydroformylation of at least oneolefin having between 3 and-19 carbon atoms per molecule.

6. A process according to claim 5 wherein said alcohol reactantcomprises the reaction product obtained by the hydroformylation of atleast one olefin having between 7 and 12 carbon atoms per molecule.

7. A process according to claim 6 wherein said aromatic carboxylic acidis phthalic anhydride.

8. A process according to claim 7 wherein said quadrivalent titaniumcompound is tetra(2-ethylhexyl) titanate.

9. A process according to claim 7 wherein said zinc dicarboxylate iszinc acetate.

10. A process according to claim 7 wherein said quadrivalent titaniumcompound is tetra(.2-ethylhexyl) titanate and said zinc dicarboxylate iszinc acetate.

11. A process for the production of diisooctyl phthalate which comprisescontacting isooctyl alcohol with phthalic anhydride under esterificationconditions in the presence of a catalyst comprising a mixture oftetra(2-ethy]hexyl) titanate and zinc acetate.

12. A process for the production of di-tridecyl phthalate whichcomprises contacting tridecyl alcohol with phthalic anhydride underesterification conditions in the presence of a catalyst comprising amixture of tetra(2- ethylhexyl) titanate and zinc acetate.

References Cited UNITED STATES PATENTS 2,727,881 12/1-955 Caldwell eta1. 260-475 3,022,333 2/1962 Kalfadelis et a1. 260-475 3,067,178 12/1962 Greenberg et al 260 -475 3,056,818 10/ 1962 Werber 2 60-475LORRAINE A. WEINBERGER, Primary Examiner.

T. L. GALLOWAY, Assistant Examiner.

US. Cl. X.R.

1. A PROCESS FOR THE PRODUCTION OF A LIGHT COLORED MONOMERIC ESTER WHICHCOMPRISES CONTACTING AN AROMATIC ORGANIC ACID REACTANT HAVING BETWEEN 1AND 4 CARBOXYL GROUPS PER MOLECULE WITH A SATURATED UNSUBSTITUTEDALIPHATIC ALCOHOL REACTANT HAVING BETWEEN 4 AND 37 CARBON ATOMS PERMOLECULE, AND WHEREIN AT LEAST ONE OF THE TWO REACTANTS ISMONOFUNCTIONAL UNDER ESTERIFICATION CONDITIONS IN THE PRESENCE OF ACATALYST COMPRISING AT LEAST ONE QUADRIVALENT TITANIUM-ORGANIC COMPOUNDHAVING THE FORMULA: